Need response. I considered crabs to be scavengers of the sea...I thought they all came to land and that made them haram. This turned out to be false. In middle eastern side, you will see crabs on land a lot, but not here. It is so rare that many people never came across one.

Same I believed to be true for oysters/clams.Beaches near me have none of them, but they are apparently caught from the water for food. Just a bit about the place:

1. These beaches are directly near the deeper side of the Pacific ocean. Waves seem overly violent.